1. Field of the Invention
The present invention relates to an inkjet printer and a control method thereof, and particularly to an ink temperature controlling mechanism and an ink temperature controlling method of the inkjet printer.
2. Description of the Related Art
As described in Japanese Unexamined Patent Publication No. 2004-276486, a temperature range for guaranteeing the ink performance is specified for an inkjet printer for the purpose of obtaining a better printing result. Therefore, there have been practically-used inkjet printers each including a heater for heating ink, and thus causes the heater to heat the ink when a lower ambient temperature makes the ink temperature lower than the temperature range for guaranteeing the ink performance.
Such an inkjet printer does not start its printing operation until the temperature of the ink rises to the temperature range for guaranteeing the ink performance. When the ambient temperature is low, the inkjet printer spends time to heat the ink, and then starts the printing operation. Particularly, the inkjet printer described in Japanese Unexamined Patent Publication No. 2006-088575 is of an ink-circulation type which circulates its ink. The inkjet printer of the ink-circulation type requires a longer time to heat the ink than an inkjet printer of a non-circulation type, because the inkjet printer of the ink-circulation needs to heat all of the circulated ink.
The inkjet printer including a heater is designed to continue heating the ink for a while until the temperature of the ink reaches a predetermined reference temperature, even after the inkjet printer completes heating the ink up to a lower limit value of the temperature range for guaranteeing the ink performance. Thereby, the inkjet printer prevents the temperature of the ink from falling below the temperature range for guaranteeing the ink quality while carrying out its printing operation. In this heating time period, the ink jet printer can also carries out a printing operation. In order for the inkjet printer to heat the ink and carry out the printing operation simultaneously, its power supply unit needs to supply the inkjet printer with both an electric power for its printing operation and an electric power for the heater.
When the power supply unit has a large capacity, the inkjet printer is supplied with a sufficient electric power for its printing operation and a sufficient electric power for the heater. However, the inclusion of the power supply unit with the large capacity in the inkjet printer causes increase in costs. When a power supply unit with a small capacity is used for the purpose of avoiding the increase in the costs, the small capacity forces the inkjet printer to stand by for starting its printing operation until the temperature of the ink rises up to its predetermined reference temperature beyond the lower limit value of the temperature range for guaranteeing the ink performance. Otherwise, the small capacity forces the power supply unit to supply the heater with an electric power controlled with consideration given to a maximum amount of electric power needed for the printing operation, and thus makes it difficult to increase the electric power to be supplied to the heater. As a result, it takes a longer time before the inkjet printer starts its printing operation.